Input (T ->O) Assembly Object (Class 0x04, Instance 0x64)

The EtherNet/IP Assembly Object Instance 0x64 defines the Input data message that will be sent from the Ethernet Port to the EtherNet/IP connection originator via an I/O message. the input data buffer is 32 bytes (16 words) and is organized as follows:

16 bits Number of bytes in Serial Output Queue

16 bits Number of bytes in Serial Input Queue

16 bits Time since last byte received (ms)

. . .

The first word provides the number of bytes/characters stored in the serial output queue. This value is identical to Class 101, Instance 1, Attribute 100. It can be used to throttle the amount of data queued to the serial device so that the Ethernet Port's 1K queue does not overflow.

The second word provides the number of bytes/characters stored in the serial input queue. This value is identical to Class 101, Instance 1, Attribute 101. It can be examined to determine when serial data needs to be read from the Ethernet Port.

The third word tells the amount of time in milliseconds (ms) since the last character was received from the serial port.